How to hang the banner of calligraphy couplets? Is it horizontal or opposite? What's the point?

You can't write banners in calligraphy couplets. If it is written as a banner, are the two sentences one or two? If it is on the page, it is called banner dialogue; If it's on two pages, it's called two banners, either of which can be hung, because it's not called couplets at all. Couplets have strict rules, and they are very particular about the content, writing format and final mounting and hanging of words.